Optimize build size: disable RTTI

    platform        | before | after
    ----------------+--------+------
    darwin-x64.node | 874K   | 867K
    linux-x64.node  | 872K   | 857K
    win32-ia32.node | 541K   | 536K
    win32-x64.node  | 700K   | 692K

Author: strager

.github/workflows/build-website.yml

@@ -22,7 +22,7 @@ jobs:
         uses: actions/checkout@v2
 
       - name: C++ configure
-        run: emcmake cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_FLAGS='-Os -flto' -DCMAKE_CXX_FLAGS='-Os -fno-rtti -fno-exceptions -flto'
+        run: emcmake cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_FLAGS='-Os -flto' -DCMAKE_CXX_FLAGS='-Os -fno-exceptions -flto'
       - name: C++ build
         run: emmake cmake --build build --target quick-lint-js-vscode quick-lint-js-vscode-licenses
       - name: C++ install

CMakeLists.txt

@@ -41,6 +41,7 @@ include(QuickLintJSCompiler)
 quick_lint_js_set_cxx_standard()
 quick_lint_js_enable_char8_t_if_supported()
 quick_lint_js_configure_exception_handling()
+quick_lint_js_configure_rtti()
 quick_lint_js_work_around_implicit_link_directories()
 quick_lint_js_enable_dead_code_stripping()
 

cmake/QuickLintJSCompiler.cmake

@@ -68,6 +68,12 @@ function (quick_lint_js_configure_exception_handling)
   endif ()
 endfunction ()
 
+# RTTI stands for Run-Time Type Information.
+function (quick_lint_js_configure_rtti)
+  quick_lint_js_add_cxx_flag_if_supported(-fno-rtti QUICK_LINT_JS_HAVE_FNO_RTTI)
+  quick_lint_js_add_cxx_flag_if_supported(/GR- QUICK_LINT_JS_HAVE_GR_)
+endfunction ()
+
 function (quick_lint_js_set_cxx_standard)
   set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
   if (cxx_std_20 IN_LIST CMAKE_CXX_COMPILE_FEATURES)
@@ -195,13 +201,20 @@ function (quick_lint_js_have_charconv OUT_VAR)
 endfunction ()
 
 function (quick_lint_js_add_c_cxx_flag_if_supported FLAG VAR)
-  check_c_compiler_flag("${FLAG}" "${VAR}_C")
-  if ("${${VAR}_C}")
+  quick_lint_js_add_c_flag_if_supported("${FLAG}" "${VAR}_C")
+  quick_lint_js_add_cxx_flag_if_supported("${FLAG}" "${VAR}_CXX")
+endfunction ()
+
+function (quick_lint_js_add_c_flag_if_supported FLAG VAR)
+  check_c_compiler_flag("${FLAG}" "${VAR}")
+  if ("${${VAR}}")
     add_compile_options($<$<COMPILE_LANGUAGE:C>:${FLAG}>)
   endif ()
+endfunction ()
 
-  check_cxx_compiler_flag("${FLAG}" "${VAR}_CXX")
-  if ("${${VAR}_CXX}")
+function (quick_lint_js_add_cxx_flag_if_supported FLAG VAR)
+  check_cxx_compiler_flag("${FLAG}" "${VAR}")
+  if ("${${VAR}}")
     add_compile_options($<$<COMPILE_LANGUAGE:CXX>:${FLAG}>)
   endif ()
 endfunction ()